The 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats emphasize the role of opioids in the perioperative space noting they are the most effective drug class for managing acute pain and therefore should be used routinely as part of the preoperative analgesic protocol.[1] However, there may be undesirable effects when using this class of drugs, including acute emesis. In human healthcare it is widely accepted that the prevention of perioperative nausea and vomiting results in better patient outcomes including recovery times, early feeding, and improved patient satisfaction.[2] Similar to humans, a significant number of dogs experience vomiting following the administration of some opioids such as morphine (50-75%) and hydromorphone (44-100%) when used as preanesthetic.[3], [4], [5], [6]

“We commonly premedicate our patients with very potent opioids, and we don’t want to give those drugs up because they provide profound analgesia,” said Tamara Grubb, DVM, PhD, DACVAA, Assistant Professor of Anesthesia & Pain Management, Washington State University College of Veterinary Medicine. “However, they often cause vomiting, which can be a problem for the anesthetist and possibly unpleasant for the patient. If the patient is very sedate from premedications or has an upper airway dysfunction, it could aspirate material into its lungs.”

Aside from the immediate concerns of managing vomiting and discomfort in the canine patient, there are other aspects of care that need to be considered. Grubb views the return to normal canine feeding as a critical indicator for the well-being of the patient. “It is an important part of normal healing as well as something we can measure. It’s not just about anesthesia, it’s about overall patient care,” she explained. “We’re adding to patient care by decreasing vomiting and then speeding up the return to normal feeding. When a dog comes home, doesn’t want to eat and possibly vomits, it does not look like a successful procedure [to a dog owner].”

A commonly used medication, maropitant citrate, is the first and only FDA approved medication for the prevention of preoperative vomiting in dogs given emetogenic agents such as opioids. In a blinded, placebo-controlled study, maropitant citrate was used preoperatively to prevent vomiting.[7] Dosing occurred 45 minutes prior to the preoperative administration of morphine, and results demonstrated a significant difference in both the incidence of vomiting (p<0.05) and in the return to feeding (p<0.05) between groups.[7]

Maropitant citrate-treated group vs. placebo group:

Incidence of vomiting: 0% vs. 93.8%

Normal feeding† 20 hours postoperative: 90.9% vs. 41.7%

Mean total food consumption: 190 grams vs. 39.1 grams

For more information on the prevention of vomiting related to preoperative use of opioids, and other resources related to the use of maropitant citrate in practice, please follow this link.

†Return to normal feeding was the time at which 100 grams of food was consumed.

About the Author:

Daniel K. Edge, DVM, MBA is a Veterinary Medical Lead for Zoetis US Companion Animal Division with focus on Pain, Oncology, and Specialty products.